:root {
  --accent: #17948e;
  --text: #1c2a2e;
  --muted: #5b6b6f;
  --border: #e3eeee;
  --page-bg: #f3f8f8;
  --card-bg: #ffffff;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  background: var(--page-bg);
  color: var(--text);
  font-family: "Poppins", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  font-size: 16px;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

header {
  background: var(--card-bg);
  border-bottom: 1px solid var(--border);
}

.header-inner {
  display: flex;
  align-items: center;
  max-width: 900px;
  margin: 0 auto;
  padding: 20px 32px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 14px;
  text-decoration: none;
}

.brand img {
  width: 48px;
  height: 48px;
  border-radius: 12px;
  display: block;
}

.brand span {
  font-size: 20px;
  font-weight: 700;
  letter-spacing: 0.03em;
  color: var(--text);
}

.brand:hover span {
  color: var(--accent);
}

main {
  max-width: 900px;
  margin: 40px auto 64px;
  padding: 56px 64px;
  background: var(--card-bg);
  border-radius: 20px;
  box-shadow:
    0 1px 2px rgba(18, 41, 45, 0.04),
    0 16px 40px rgba(18, 41, 45, 0.06);
}

h1 {
  text-align: left;
  font-size: 40px;
  line-height: 1.2;
  margin: 0 0 4px;
  color: var(--text);
}

h1 span {
  display: block;
  color: var(--accent);
  font-size: 26px;
  font-weight: 600;
  margin-top: 8px;
}

.updated {
  text-align: left;
  color: var(--muted);
  font-size: 14px;
  margin: 16px 0 32px;
  padding-bottom: 32px;
  border-bottom: 1px solid var(--border);
}

h2 {
  font-size: 19px;
  margin: 40px 0 14px;
  padding-top: 24px;
  border-top: 1px solid var(--border);
  color: var(--text);
}

section:first-of-type h2 {
  border-top: none;
  padding-top: 0;
  margin-top: 32px;
}

p {
  margin: 0 0 14px;
}

ul {
  margin: 0 0 14px;
  padding-left: 20px;
}

li {
  margin-bottom: 8px;
}

a {
  color: var(--accent);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

strong {
  font-weight: 600;
}

.screens {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
  margin: 8px 0 4px;
}

.screens img {
  width: 100%;
  height: auto;
  display: block;
  border-radius: 16px;
  border: 1px solid var(--border);
  box-shadow: 0 8px 20px rgba(18, 41, 45, 0.1);
}

.page-footer {
  max-width: 900px;
  margin: 0 auto;
  padding: 0 32px 64px;
  text-align: center;
  color: var(--muted);
  font-size: 13px;
}

.page-footer a {
  color: var(--muted);
  text-decoration: underline;
}

.page-footer a:hover {
  color: var(--accent);
}

@media (max-width: 640px) {
  .header-inner {
    padding: 16px 20px;
  }

  main {
    padding: 36px 24px;
    border-radius: 16px;
    margin: 24px auto 48px;
  }

  h1 {
    font-size: 30px;
  }

  h1 span {
    font-size: 20px;
  }

  .screens {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (prefers-color-scheme: dark) {
  :root {
    --text: #eef5f5;
    --muted: #9fb1b3;
    --border: #253235;
    --page-bg: #0b1214;
    --card-bg: #131c1f;
  }

  main {
    box-shadow:
      0 1px 2px rgba(0, 0, 0, 0.3),
      0 16px 40px rgba(0, 0, 0, 0.35);
  }
}